easier to read

src/diff/children.js

@@ -320,16 +320,8 @@ function constructNewChildrenArray(newParentVNode, renderResult, oldChildren) {
 					skew--;
 				}
 			} else if (matchingIndex < skewedIndex) {
-				// Our matched DOM-node is further in the negative way in the list of children
-				// than where it's at now.
-
-				// When the remaining old chiildren is less than the new children
-				// plus our skewed index we know we are dealing with a growing list
-				if (remainingOldChildren < newChildrenLength + skewedIndex) {
-					skew += matchingIndex + skewedIndex;
-				} else {
-					skew = 0;
-				}
+				// When our new position is in front of our old position than we increase the skew
+				skew++;
 			}
 
 			// Move this VNode's DOM if the original index (matchingIndex) doesn't

test/browser/render.test.js

@@ -1636,7 +1636,9 @@ describe('render()', () => {
 		);
 		const a = ['0', '1', '2', '3', '4', '5', '6'];
 		const b = ['1', '3', '5', '2', '6', '4', '0'];
+		const c = ['11', '3', '1', '4', '6', '2', '5', '0', '9', '10'];
 		render(<App items={a} />, scratch);
+		clearLog();
 		expect(scratch.innerHTML).to.equal(
 			`<div>${a.map(n => `<div>${n}</div>`).join('')}</div>`
 		);
@@ -1645,10 +1647,46 @@ describe('render()', () => {
 		expect(scratch.innerHTML).to.equal(
 			`<div>${b.map(n => `<div>${n}</div>`).join('')}</div>`
 		);
+		expect(getLog()).to.deep.equal([
+			'<div>0123456.insertBefore(<div>2, <div>6)',
+			'<div>0134526.appendChild(<div>4)',
+			'<div>0135264.appendChild(<div>0)'
+		]);
+		clearLog();
+
+		render(<App items={c} />, scratch);
+		expect(scratch.innerHTML).to.equal(
+			`<div>${c.map(n => `<div>${n}</div>`).join('')}</div>`
+		);
+		expect(getLog()).to.deep.equal([
+			'<div>.appendChild(#text)',
+			'<div>1352640.insertBefore(<div>11, <div>1)',
+			'<div>111352640.insertBefore(<div>1, <div>5)',
+			'<div>113152640.insertBefore(<div>6, <div>0)',
+			'<div>113152460.insertBefore(<div>2, <div>0)',
+			'<div>113154620.insertBefore(<div>5, <div>0)',
+			'<div>.appendChild(#text)',
+			'<div>113146250.appendChild(<div>9)',
+			'<div>.appendChild(#text)',
+			'<div>1131462509.appendChild(<div>10)'
+		]);
+		clearLog();
 
 		render(<App items={a} />, scratch);
 		expect(scratch.innerHTML).to.equal(
 			`<div>${a.map(n => `<div>${n}</div>`).join('')}</div>`
 		);
+		expect(getLog()).to.deep.equal([
+			'<div>11.remove()',
+			'<div>9.remove()',
+			'<div>10.remove()',
+			'<div>3146250.appendChild(<div>1)',
+			'<div>3462501.appendChild(<div>2)',
+			'<div>3465012.appendChild(<div>3)',
+			'<div>4650123.appendChild(<div>4)',
+			'<div>6501234.appendChild(<div>5)',
+			'<div>6012345.appendChild(<div>6)'
+		]);
+		clearLog();
 	});
 });